Function foreach

src/tests/fetcher_cache_tests.cpp:249–251

  if (entries.isSome()) {
    cout << "Begin listing sandbox `" << path.string() << "`:" << endl;
    foreach (const string& entry, entries.get()) {
      logFile(path, entry);
    }
    cout << "End sandbox" << endl;
  } else {
    cout << "Could not list sandbox `" << path.string()